Biodiesel, a renewable biofuel obtained from vegetable oils or animal fats, has
emerged as a sustainable alternative to fossil fuels. This fuel has stood out
for its ability to reduce greenhouse gas emissions, helping to mitigate
environmental impacts. Biodiesel is produced by reacting oil with an alcohol in
the presence of a catalyst, which can be homogeneous or heterogeneous.
Heterogeneous catalysis has advantages such as ease of separation, greater
tolerance to oils with a high fatty acid content and the possibility of reusing
the catalyst, which reduces costs and minimizes waste generation. Among the
various heterogeneous catalysts available, niobium-based compounds stand out.
The use of niobium-based catalysts is advantageous due to the vast reserves of
this element in Brazil, guaranteeing autonomy in production and strengthening
the national biofuels industry. This work investigated the production of
biodiesel from soybean oil using the homogeneous and heterogeneous
transesterification routes. The homogeneous route used 0.7% KOH dissolved in
methanol, operating at 60 °C for 1 hour with a methanol:oil molar ratio of 6:1.
The heterogeneous route used a solid K2O catalyst supported on
Nb2O5, in a ratio of 4% by mass, with a molar ratio of
10:1 and a reaction time of 4 hours. The yield obtained was 85% for the
homogeneous route and 90% for the heterogeneous route. The biodiesel from the
homogeneous route had a slightly basic pH, requiring neutralization with
hydrochloric acid, while the product from the heterogeneous route had a neutral
pH, requiring no additional treatment. The results indicate that although the
homogeneous route is faster and uses less catalyst, the heterogeneous route has
advantages in terms of yield and quality of the final product, as well as less
environmental impact. Heterogeneous catalysts such as
K2O/Nb2O5 are therefore promising for the
sustainable production of biodiesel.